Natural and human forcing in recent geomorphic change; case studies in the Rio de la Plata basin

An analysis of geomorphic system's response to change in human and natural drivers in some areas within the Río de la Plata basin is presented. The aim is to determine whether an acceleration of geomorphic processes has taken place in recent years and, if so, to what extent it is due to natural (climate) or human (land-use) drivers. Study areas of different size, socio-economic and geomorphic conditions have been selected: the Río de la Plata estuary and three sub-basins within its watershed. Sediment cores were extracted and dated (²¹⁰Pb) to determine sedimentation rates since the end of the 19th century. Rates were compared with time series on rainfall as well as human drivers such as population, GDP, livestock load, crop area, energy consumption or cement consumption, all of them related to human capacity to disturb land surface. Data on river discharge were also gathered. Results obtained indicate that sedimentation rates during the last century have remained essentially constant in a remote Andean basin, whereas they show important increases in the other two, particularly one located by the São Paulo metropolitan area. Rates in the estuary are somewhere in between. It appears that there is an intensification of denudation/sedimentation processes within the basin.Rainfall remained stable or varied very slightly during the period analysed and does not seem to explain increases of sedimentation rates observed. Human drivers, particularly those more directly related to capacity to disturb land surface (GDP, energy or cement consumption) show variations that suggest human forcing is a more likely explanation for the observed change in geomorphic processes. It appears that a marked increase in denudation, of a “technological” nature, is taking place in this basin and leading to an acceleration of sediment supply. This is coherent with similar increases observed in other regions.     

Catalytic performance of silica-aluminas synthesised with the help of chitosan biopolymer

Mesoporous amorphous silica-aluminas were synthesised with standard aluminium and silicon sources by means of the formation of inorganic–organic composites with the addition of chitosan biopolymer, and compared to analogous catalysts synthesised conventionally. Some catalysts were subjected to hydrothermal treatment. The resulting specific surface areas were from 480 to 573 m²/g in the untreated samples and 300–430 m²/g in the hydrotreated catalysts, average pore sizes ranging from 32 to 100 Å with sharp, unimodal distributions. The chitosan materials showed higher specific surface areas and larger pore sizes than those of their non-chitosan counterparts. The most important differences in the acidic properties were in the relationships between tetrahedral and octahedral aluminium atoms, the chitosan materials having higher relative amounts of tetrahedral aluminium than the conventional silica-aluminas. Evidences of stabilization in the physical and chemical properties were observed in the chitosan-containing catalysts. The catalytic performance was evaluated with the conversion of tri-isopropylbenzene at 400 °C, to assess activity and accessibility, and cyclohexene at 300 °C, to assess hydrogen transfer properties. The highest activity and accessibility was observed in the hydrotreated, chitosan-containing catalyst, while hydrogen transfer capabilities were similar to those of medium unit cell sizes, equilibrium commercial FCC catalysts.     

“Click” Synthesis of a Heterobifunctional Ferrocenyl Dendrimer with Molecular Recognition Properties and Influence of the Ferrocenyl Redox Potential on the Formation of Gold Nanoparticles

Alkyne protection by complexation of ethynylferrocene with dicobalt octacarbonyl followed by regioselective acetylation, then deprotection and “click” reaction with a nona-azido-terminated arene-cored dendrimer leads to the heterodifunctional nona(1,2,3-triazolyl-acetylferrocenyl) dendrimer. Cyclic voltammetry of this metallodendrimer shows recognition of both ATP^2? and Pd²⁺. HAuCl₄ is reduced much more slowly to gold nanoparticles by the nona(triazolyl-acetylferrocenyl dendrimer than by the nona(triazolylferrocenyl) dendrimer due to the shift of redox potential in the new heterodifunctional dendrimer compared to that of the parent ferrocenyl dendrimer.     

Taioba (Xanthosoma sagittifolium) Leaves: Nutrient Composition and Physiological Effects on Healthy Rats

Several studies have shown that fruits and vegetables contribute to protect against degenerative pathologies such as cardiovascular diseases, diabetes, and cancer, mainly due to the presence of dietary fiber (DF) and polyphenols. Taioba (Xanthosoma sagittifolium) is an edible aroid widely grown in many parts of Africa, America, and Asia. The tubers portions of taioba are widely consumed; however, the leafy portions are generally discarded, despite their high nutritive value. In this study, we have partly characterized the DF of lyophiized taioba leaf (LTL), and assessed the possible protective effects on biochemical parameters and on bile acid (BA) production in colon and cecum, when fed to healthy rats for 4 wk. Forty‐five Wistar rats were assigned to either of 5 groups: group 1 received AIN 93G diet (CG: Control); group 2 received AIN 93G containing 2.5% of cellulose + 2.5% inulin (CEIN_5%); group 3 received AIN 93G containing 2.5% of cellulose + 2.5% taioba fiber (CETA_5%); group 4 received AIN 93G containing 5% cellulose + 2.5% taioba fiber (CETA_7.5%); group 5 received AIN 93G containing 5% cellulose + 2.5% of inulin (CEIN_7.5%). LTL showed high contents of total fiber, predominantly comprising insoluble DF with glucose as the major monomer. Rats receiving LTL had increased fecal mass and fat excretion, and improved BA profiles by diminishing the proportion of secondary acids, thus suggesting that consumption of taioba leaf may have the property of lowering the risk of colon cancer.     

Parameter reference immutability: formal definition, inference tool, and comparison

Knowing which method parameters may be mutated during a method’s execution is useful for many software engineering tasks. A parameter reference is immutable if it cannot be used to modify the state of its referent object during the method’s execution. We formally define this notion, in a core object-oriented language. Having the formal definition enables determining correctness and accuracy of tools approximating this definition and unbiased comparison of analyses and tools that approximate similar definitions. We present Pidasa, a tool for classifying parameter reference immutability. Pidasa combines several lightweight, scalable analyses in stages, with each stage refining the overall result. The resulting analysis is scalable and combines the strengths of its component analyses. As one of the component analyses, we present a novel dynamic mutability analysis and show how its results can be improved by random input generation. Experimental results on programs of up to 185 kLOC show that, compared to previous approaches, Pidasa increases both run-time performance and overall accuracy of immutability inference.     

Characterization by culture-dependent and culture-independent methods of the bacterial population of suckling-lamb packaged in different atmospheres

This study offers insight into the dynamics of bacterial populations in fresh cuts of suckling lamb under four different atmospheric conditions: air (A), and three Modified Atmosphere Packaging (MAP) environments, 15%O₂/30%CO₂/55%N₂ (C, commercial), 70%O₂/30%CO₂ (O), and 15%O₂/85%CO₂ (H) for 18 days. Microbial analyses by both conventional methods and PCR-DGGE were performed. Controversial and surprising results emerged from comparing both methods in relation to the genus Pseudomonas. Thus, conventional methods detected the presence of high numbers of Pseudomonas colonies, although PCR-DGGE only detected this genus in air-packaged samples. PCR-DGGE detected higher microbial diversity in the control samples (A) than in the modified atmospheres (C, O, H), having atmosphere H the fewest number of species. Brochothrix thermosphacta, LAB (Carnobacterium divergens and Lactobacillus sakei), and Escherichia spp. were detected in all the atmospheres throughout storage. Moreover, previously undescribed bacteria from lamb meat such as Enterobacter hormaechei, Staphylococcus equorum and Jeotgalicoccus spp. were also isolated in this study by DGGE. Additionally, qPCR analysis was used to detect and characterize strains of Escherichia coli. Virulence genes (stx₁, stx₂ and eae) were detected throughout storage in 97% of the samples. A high CO₂ atmosphere was the most effective packaging combination doubling storage time in comparison with commercial atmosphere.     

Effect of raspberry pomace extracts isolated by high pressure extraction on the quality and shelf‐life of beef burgers

Raspberry pomace extracts isolated with supercritical carbon dioxide (SCE) and pressurised ethanol/water (ETE) were tested in beef burgers. Only ETE additives effectively inhibited lipid oxidation and the growth of microorganisms, as it was observed by measuring the changes of thiobarbituric acid reactive substances, bacterial counts and the content of O₂ and CO₂ during storage in the modified atmosphere package. ETE additives also demonstrated some meat colour preservation effects, which were assessed by the intensity of hamburger colour and metmyoglobin concentration. However, ETE additives did not alter burger's taste at the applied concentrations (up to 1%). It may be concluded that the most effective extracts possessing strong antioxidant and antimicrobial activity may be isolated from raspberry pomace by the pressurised liquid extraction with a hydroethanolic solvent; such extracts may be considered as promising additives in meat products for improving their stability and enriching with beneficial to health phytochemicals.     

The role of familiarity in daily well-being: Developmental and cultural variation.

The present study examined life stage and cultural differences in the degree to which familiarity of one's physical location and interaction partner is associated with daily well-being. Participants reported all the activities they engaged in and how they felt during these activities on a previous day using the Day Reconstruction Method (Kahneman, Krueger, Schkade, Schwarz, & Stone, 2004). Both Korean and American retirees were happier when in a familiar place than in an unfamiliar place, whereas the reverse was true for both Korean and American working adults. In addition, we found cultural differences in the role of familiarity of the interaction partner. Specifically, Koreans (both retirees and working adults) were substantially happier when they interacted with a familiar person than when they interacted with an unfamiliar person. In contrast, Americans (both retirees and working adults) were no happier with a familiar person than with an unfamiliar person. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Finite element simulation to design constructive elements: An application to light gypsum plaster for partitions

In the past decade finite element simulation has become a very useful methodological tool in the different science fields. This article offers a specific application of this powerful mechanism used for analyzing the mechanical behaviour of constructive elements in the design phase, prior to the laboratory tests’ stage. The aim of applying this simulation is to minimize the high cost the real scale fabrication of these elements entails.This research focuses on the analysis by finite element simulations (FES) of several construction elements used as interior partitions and made of plaster lightened with cork. The results of the study will allow us to determine the most suitable thickness values and proportions to ensure that the requirements stated by the standards and norms for light partitions are fulfilled. These parameters will later be useful for the final laboratory tests.Two simulation groups have been developed using the ANSYS application: firstly, a partition leaf of 200 × 260 cm is studied exposing it to a superficial load and to an eccentric load following the EUAtc common directives for the technical appreciation of light panels, 1973). Second, the behaviour of a panel with a through opening is tested with the simulation regarding the different hypothesis of the structure deformation supporting and surrounding it.Finally, it is proved that the element of thickness 7 cm and proportions stated at the beginning ensure a good performance regarding strain without producing any visible fissures, and therefore are suitable for a further laboratory test on real models.